18213805 has 8 divisors (see below), whose sum is σ = 22447512. Its totient is φ = 14177088.

The previous prime is 18213803. The next prime is 18213823. The reversal of 18213805 is 50831281.

It can be written as a sum of positive squares in 4 ways, for example, as 10673289 + 7540516 = 3267^2 + 2746^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 18213805 - 2¹ = 18213803 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18213803) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 49042 + ... + 49411.

It is an arithmetic number, because the mean of its divisors is an integer number (2805939).

Almost surely, 2^18213805 is an apocalyptic number.

It is an amenable number.

18213805 is a deficient number, since it is larger than the sum of its proper divisors (4233707).

18213805 is an equidigital number, since it uses as much as digits as its factorization.

18213805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 98495.

The product of its (nonzero) digits is 1920, while the sum is 28.

The square root of 18213805 is about 4267.7634657980. The cubic root of 18213805 is about 263.1077016517.

The spelling of 18213805 in words is "eighteen million, two hundred thirteen thousand, eight hundred five".